一、准备工作
1.定义一个父组件，名字为Parent
/src/component/Parent.js
import React, {Component} from 'react'
export default class Parent extends Component {
constructor(props) {
super(props)
this.state = {
name: '我是父组件',
msg: '父组件传值给子组件'
}
}
render() {
return (
<div>
<h2>{ this.state.name }</h2>
</div>
)
}
}
2.定义一个子组件 ，名字为Children
/src/component/Children.js
import React, {Component} from 'react'
export default class Children extends Component {
constructor(props) {
super(props)
this.state = {
name: '我是子组件',
msg: '子组件传值给父组件'
}
}
render() {
return (
<div>
<h2>{ this.state.name }</h2>
</div>
)
}
}
3.先在App.js里引入父组件Parent
/src/App.js
import React from 'react';
import Parent from './component/Parent'
function App() {
return (
<div>
<Parent/>
</div>
);
}
export default App;
运行项目：
编译成功
界面如图所示，http://localhost:3000/
4.父组件Parent引入子组件Children
import React, {Component} from 'react'
import Children from './Children'
export default class Parent extends Component {
constructor(props) {
super(props)
this.state = {
name: '我是父组件',
msg: '父组件传值给子组件'
}
}
render() {
return (
<div>
<h2>{ this.state.name }</h2>
<h3>我要引入子组件了：</h3>
<hr/>
<Children/>
</div>
)
}
}
已成功引入子组件
二、子组件Children传值(msg)给父组件Parent
子组件传值给父组件的步骤：
- 父组件在调用子组件时，传入一整个组件给子组件
<Children parent={ this } /> - 父组件中定义一个方法
getChildrenMsg(resulet, msg)，用来获取子组件传来的值以及执行其他操作 - 子组件在通过
this.props来获取到一整个组件this.props.parent或者this.props[parent] - 子组件调用父组件步骤2里定义的方法，通过bind绑定传值
Parent:
import React, {Component} from 'react'
import Children from './Children'
export default class Parent extends Component {
constructor(props) {
super(props)
this.state = {
name: '我是父组件',
msg: '父组件传值给子组件',
childrenMsg: ''
}
}
getChildrenMsg = (result, msg) => {
// console.log(result, msg)
// 很奇怪这里的result就是子组件那bind的第一个参数this，msg是第二个参数
this.setState({
childrenMsg: msg
})
}
render() {
return (
<div>
<h2>{ this.state.name }</h2>
<h3>子组件传来的值为：{ this.state.childrenMsg }</h3>
<h3>我要引入子组件了：</h3>
<hr/>
<Children parent={ this } />
</div>
)
}
}
Children:
import React, {Component} from 'react'
export default class Children extends Component {
constructor(props) {
super(props)
this.state = {
name: '我是子组件',
msg: '子组件传值给父组件'
}
}
toParent = () => {
// console.log(this.props.parent.getChildrenMsg.bind(this, this.state.msg))
this.props.parent.getChildrenMsg(this, this.state.msg)
}
render() {
return (
<div>
<h2>{ this.state.name }</h2>
<button onClick={ this.toParent }>子组件传入给父组件</button>
</div>
)
}
}
三、子组件Children给父组件Parent传一整个组件（父组件获取整个子组件）
子组件给父组件传一整个组件（父组件获取整个子组件）的步骤：
- 父组件在调用子组件时，通过ref属性，拿到整个子组件
<Children ref='children'> - 父组件中通过
this.refs.children或者this.refs[children]获取到一整个子组件实例（注意，要在DOM加载后才能获取）
Parent:
import React, {Component} from 'react'
import Children from './Children'
export default class Parent extends Component {
constructor(props) {
super(props)
this.state = {
name: '我是父组件',
msg: '父组件传值给子组件',
childrenMsg: ''
}
}
getChildrenMsg = () => {
this.setState({
childrenMsg: this.refs['children'].state.msg
})
}
render() {
return (
<div>
<h2>{ this.state.name }</h2>
<button onClick={ this.getChildrenMsg }>获取更新子组件的msg值</button>
<h3>子组件传来的值为：{ this.state.childrenMsg }</h3>
<h3>我要引入子组件了：</h3>
<hr/>
<Children ref="children" />
</div>
)
}
}
Children:
import React, {Component} from 'react'
export default class Children extends Component {
constructor(props) {
super(props)
this.state = {
name: '我是子组件',
msg: '子组件传值给父组件'
}
}
render() {
return (
<div>
<h2>{ this.state.name }</h2>
<h3>子组件的msg为：{ this.state.msg }</h3>
</div>
)
}
}
初始页面，点击按钮
点击按钮后
四、子组件Children给父组件Parent传方法
在第三点获取到整个组件的前提上，再获取方法，所以不详细讲了。
